Commercial trucking provides a substantial proportion of commercial transportation of goods throughout the world. One common type of commercial truck is a tractor trailer, which includes a semi-trailer coupled with a road tractor. The term “semi-trailer” typically refers to a trailer having one or more rear axles and no front axles. During operation, a large proportion of the weight of the semi-trailer is supported either by the road tractor or by a detachable front axle assembly known as a dolly. Semi-trailers are also normally equipped with legs that can be lowered to support the semi-trailer when it is uncoupled from the dolly or the road tractor.
As used herein, the term, “commercial motor vehicle” refers to any self-propelled or towed motor vehicle for use on a highway in interstate commerce to transport passengers or property and having a gross vehicle weight rating of 4,536 kilograms (approximately 10,000 pounds) or more. As used herein, the term, “gross vehicle weight rating” is the maximum allowable weight of a fully equipped tow vehicle including passengers and cargo. As used herein, the term, “Class A commercial motor vehicle” refers to any commercial vehicle having a gross vehicle weight rating (“GVWR”) of at least 11,793 kilograms (approximately 26,000 pounds).
Currently, in the United States, semi-truck trailers are on the order of 40 to 53 feet long and have a rear swing door providing an opening of about 110 inches high and 100 inches wide. Trucking operators seek to maximize the utilization of interior space within the trailer. Forklift trucks are typically used to load cargo into trailers. Specifically, cargo is supported by a pallet, which is lifted vertically by the forklift truck and deposited in the trailer. It is common for the forklift truck or other loading machine to push cargo from the rear open door of the trailer toward the front.
The typical trailer construction utilizes a roof of sheet metal or other opaque sheet material supported by a number of transversely extending reinforcing ribs or bows. These bows are exposed to the inside of the trailer and form irregularities on the inside surface of the trailer roof. During the loading process, it is unfortunately common for cargo to come in contact with one of the bows, potentially causing damage to the roof structure. Due to fear of damaging trailers in this manner, operators are often not able to fully utilize the interior capacity of the trailer. Damage to internally exposed roof bows during the cargo loading and unloading process imposes a significant operating cost burden on motor carrier operators and can cause shipping delays.
During the loading or unloading processes, it is also unfortunately common for cargo to come into contact with the rear frame of the trailer. For example, cargo may contact the upper portion of the rear door frame, thereby potentially causing structural damage to the trailer and/or the cargo. Specifically, the upper portion of the rear door frame of the trailer generally extends perpendicularly from the roof panel such that cargo contacting the upper portion causes a relatively abrupt collision between the respective structures, especially during the unloading process when the cargo is being transported relatively close to the roof inner surface.
Additionally, the bows are currently secured to the inside of the trailer by a plurality of fasteners. However, during installation, the bows may be displaced or misaligned before being secured to the trailer by the fasteners. Misalignment of the bows may cause irregularities in the roof structure or a weakened connection between the bows and the trailer.
Furthermore, the opaque nature of currently-known trailer roofs causes the cargo space within the trailer to be generally void of natural light. Therefore, artificial light typically must be provided during loading and unloading of the cargo space.